AQA GCSE Food Preparation and Nutrition: Revision Guide

Food Safety > Food spoilage and contamination Nutrients Key learning: PROTEIN What it is and what it is made of • Protein is a macronutrient which is found in animal and plant foods • Protein molecules are made up of ‘building blocks’ called amino acids • Proteins are very large molecules • There are at least 20 amino acids Why amino acids are important • 10 amino acids are essential for children • 8 amino acids are essential for adults • High biological value (HBV) proteins contain all 10 essential amino acids • Low biological value (LBV) proteins are missing one or more essential amino acids • We must get essential amino acids from the food we eat (other amino acids can be made in our bodies from protein foods we eat) • If you eat two or more LBV protein foods together you will get all the essential amino acids • This is called protein complementation: e.g. beans on toast, lentil soup and bread, rice and peas, nut butter on bread, rice and bean salad What protein does in the body (its functions) Protein is needed for: • Body growth • Repair of the body when it is injured • Giving the body energy • Protein is needed by plants and animals • Children are growing so they need more essential amino acids than adults • The body will only use protein for energy if it does not have enough from carbohydrates and fats • Proteins are also needed to make other essential things, e.g.: − hormones, e.g. to make you grow − enzymes, e.g. to digest your food − antibodies, e.g. to help you fight infections 1 Book-link: 1.1.1 Protein, pages 2–9 Chapter 1: Nutrients Protein What you must know about protein In your answers, you need to know how to explain: Further information you can add to extend your answers: What do you need to know? You need to know about the importance of nutrients and water for our health. Nutrients are natural chemicals found in foods that are needed by the body for different reasons. Next you need to know: • The different nutrients: Macronutrients (protein, fat, carbohydrate) Micronutrients (vitamins, minerals) • The functions of nutrients and water in the body (what they do) • The main sources of nutrients and water (which foods they are found in) • The effects of a deficiency (not enough) or excess (too much) of a nutrient and water on the body • The amount of nutrients and water needed every day for different life stages 326